#include<stdio.h>

/* 全局变量声明*/
int g;

int main()
{
    /* 局部变量声明*/
    int a , b;

    /*实际初始化*/
    a = 10;
    b = 20;
    g = a + b;

    printf("value of a = %d, b = %d and g = %d\n", a, b, g);
    return 0;
}